$ rails g devise:views:bootstrap_templates -f
This will automatically apply the bootstrap style to all devise view files.

Code written by default in the devise view file
<div class="container">
  <div class="row">
    <div class="mx-auto" style="width: 580px;">
    </div>
  </div><!-- End of row -->
</div><!-- End of container -->
If you surround it with this,

Good vibes!